动态改变div的z-index属性的简单实例

<script language="javascript"> 
var MAX_INDEX=4; 
function change(ddd) 
{ 
if(ddd.style.zIndex<= MAX_INDEX) 
{ 
ddd.style.zIndex = MAX_INDEX+1; 
MAX_INDEX++; 
} 
} 
</script> 
<div id="layer1" onclick="javascript:change(this);" style="position:absolute;margin-left:100;margin-top:50px;margin-=100;width=100;height=100;background-color:#ff0000;z-index:1"></div> 
<div id="layer2" onclick="javascript:change(this);" style="position:absolute;margin-left:120;margin-top:60px;margin-=120;width=100;height=100;background-color:#00ff00;z-index:2"></div> 
<div id="layer3" onclick="javascript:change(this);" style="position:absolute;margin-left:140;margin-top:70px;margin-=140;width=100;height=100;background-color:#0000ff;z-index:3"></div> 
<div id="layer4" onclick="javascript:change(this);" style="position:absolute;margin-left:160;margin-top:80px;margin-=160;width=100;height=100;background-color:#000000;z-index:4"></div>